The A’s spent the winter looking for a left-handed reliever, and with just more than two weeks to go before camp opens, the team finally added one — along with a familiar face.

Oakland reacquired happy-go-lucky fan favorite Brandon Moss, a member of the A’s 2012-14 postseason teams, in a deal that also brought in the team’s final bullpen addition, lefty Ryan Buchter. Minor-league starters Jesse Hahn and Heath Fillmyer went to Kansas City in the trade.

“When I got the news, I was jumping and screaming,” Moss told The Chronicle by phone. “Not because I didn’t like K.C., I loved it there, but because it’s Oakland, and because Bob Melvin is still the manager there.”

It’s uncertain how long the A’s will hang on to Moss, who these days is mostly a designated hitter. Oakland traded promising infielder Ryon Healy this winter to make room for Khris Davis to take over the DH spot, and there’s zero chance the A’s would platoon Davis. So Moss, 34, might be a short-timer with Oakland should the team swing any other deals before spring training. He might also provide spring depth in the event of an injury.

“It’s not entirely clear how he would fit into our 25-man roster at this time,” A’s general manager David Forst said. “The great thing is we don’t have to put together a 25-man roster right now. We’ll see how it plays out over the next couple of months. Brandon is a great guy to have around. Everyone to a man loved having him here, and I’ve already heard from a number of people who are excited about having him back.”

Moss was signed to a minor-league deal in 2012 and eventually became one of the team’s top power hitters, so he’s approaching this trade the same way. “I’m going to make them figure something out,” he said, adding with a laugh, “I’m going to rake all spring and they’re going to have to keep me.

“I understand I’m not much of a fit right now, but I want to make this work as well as possible. I can’t tell you how much I wanted this move, the chance to go back to Oakland, and I have faith if I have an opportunity there, I’ll make it happen. I’ve done it before.”

Moss, who hit .207 with 22 homers, 50 RBIs and 128 strikeouts in 362 plate appearances last year, likely was acquired to help get the deal completed; he is making $7.25 million this season, and there is a $1 million buyout on his 2019 option. The Royals sent $3.25 million to help cover a chunk of that, but it’s still a good deal financially for Kansas City, which is rebuilding.

Forst said that the A’s tried to sign Buchter as a minor-league free agent before the 2015 season and have kept tabs on him since then; his velocity is now up to 92-93 mph, and “he checked a lot of boxes for us,” Forst said.

“I knew they wanted me and I guess that ‘no’ wasn’t good enough for them,” Buchter joked on a conference call. “They found their way back around to acquiring me. ... I’m definitely excited. It’s good to be where you’re wanted, and I definitely like the direction Oakland is heading in.”

Before Monday’s deal, Daniel Coulombe was the only left-handed reliever on Oakland’s 40-man roster. The A’s had tried to land several free-agent lefty relievers, including Brian Duensing, who took $3 million less than Oakland offered in order to return to the Cubs.

Buchter, 30, allowed opponents a .187 average last season, including .176 against left-handed hitters. He was 1-0 with a 2.67 ERA in 29 outings with the Royals after coming from San Diego in a July trade, and his overall ERA last season was 2.89.

“I like Buchter a lot,” one American League scout said. “He’s a solid seventh-inning guy, fastball-cutter. He’s a little like Sean Doolittle, he competes. And he can go more than one inning.”

Hahn, 28, had fallen out of favor with the A’s the past two years after numerous injuries, and he spent much of his time at Triple-A Nashville. Acquired from San Diego in the Derek Norris deal after the 2014 season, he went 3-6 with a 5.30 ERA in 14 games (13 starts) with Oakland last year.

“It was an up-and-down ride here for Jesse, a lot of times through no fault of his own,” Forst said. “He ran into some bad injury luck, but he did bust it to try to get out there. It was going to be an uphill climb for him this spring, being out of options.”

Fillmyer, 23, was 22-24 with a 3.78 ERA in 84 games, including 75 starts, over four seasons in the A’s organization after being chosen in the fifth round in 2014.